ESU buys and sells new, used and surplus Circuit Breakers of most manufacturers and voltages
Electrical Supplies Unlimited (ESU) provides a comprehensive selection of high-quality circuit breakers for residential, commercial, and industrial applications. Residential breakers are commonly used in home electrical panels to protect circuits from overloads and short circuits. These breakers automatically cut off power when a fault is detected, preventing fires and equipment damage. Commercial breakers operate on the same principle but are built to handle higher voltages and more demanding electrical loads typically found in offices, retail buildings, and industrial facilities. ESU also offers popout resettable breakers, which feature a convenient button that "pops out" when tripped, allowing for easy manual reset without replacement—ideal for repeated-use circuits and safety-critical systems.
In addition to traditional circuit protection, ESU stocks specialized components such as DIN rail mounted breakers, which are widely used in industrial and automation control panels. These compact units snap into standardized DIN rails, making installation simple and scalable for complex systems. Popout resettable breakers are also available in DIN-mounted form for streamlined panel integration. To further enhance safety and functionality, ESU provides a variety of breaker accessories, including lockout devices, mounting hardware, and labels, enabling users to customize and secure their breaker setups according to specific code requirements or operational needs. Whether you're outfitting a residential panel or an industrial control cabinet, ESU has the right circuit protection solution.Circuit breakers are electrical switches designed to protect an electrical circuit from damage caused by overload or short circuit.
If a circumstance arises where a fault condition occurs, the switch discontinues electrical flow. This circuit breaker can be reset either manually or automatically. In contrast, a fuse must be replaced when it operates one time.
Circuit breakers are made in varying sizes, from small devices that protect an individual household appliance up to large switchgear
designed to protect high voltage circuits feeding an entire city.
Types of Circuit Breakers
Low voltage circuit breakers
Medium-voltage circuit breakers
High-voltage circuit breakers
Magnetic circuit breakers
Thermal magnetic circuit breakers
Common trip breakers
Tandem Circuit Breakers
Operation
All circuit breakers have common features in their operation, although details vary substantially depending on the voltage class, current rating and type of the circuit breaker.
The circuit breaker must detect a fault condition; in low-voltage circuit breakers this is usually done within the breaker enclosure. Circuit breakers for large currents or high voltages are usually arranged with pilot devices to sense a fault current and to operate the trip opening mechanism. The trip solenoid that releases the latch is usually energized by a separate battery, although some high-voltage circuit breakers are self-contained with current transformers, protection relays, and an internal control power source.